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将一小物块轻放在足够长的水平传送带上,之后物块在传送带上运动的v﹣t图象如图所示,设物块与传送带间的动摩擦因数为μ,则下列说法中正确的是( )
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如图所示x轴与水平传送带重合坐标原点O.在传送带的左端传送带长L.=8m并以恒定速率运转一质量m=1
如图所示一水平传送带以速度v1向右匀速传动某时刻有一物块以水平速度v2从右端滑上传送带物块与传送带间
如果物块能从左端离开传送带,它在传送带上运动的时间一定比传送带不转动时运动的时间长
如果物块还从右端离开传送带,则整个过程中,传送带对物块所做的总功一定不会为正值
如果物块还从右端离开传送带,则物块的速度为零时,传送带上产生的滑痕长度达到最长
物块在离开传送带之前,一定不会做匀速直线运动
如图所示x轴与水平传送带重合坐标原点O.在传送带的左端传送带长L.=8m匀速运动的速度v0=5m/s
如图所示水平传送带向右匀速运动的速度v﹣2m/s.一小物块以水平向右的速度v0=8m/s滑上传送带已
如图所示的传送带其水平部分ab的长度为2m倾斜部分bc的长度为4mbc与水平面的夹角为θ=370将一
如图所示绷紧的水平传送带足够长始终以v1=2m/s的恒定速率运行.初速度大小为v2=3m/s的小墨块
17分将粉笔头A.轻放在以2m/s的恒定速度运动的足够长水平传送带上后传送带上留下一条长度为4m的划
如图所示一足够长的水平传送带以v=2m/s的速度匀速顺时针转动运动.将一质量为m=1kg的物块无初速
将粉笔头A.轻放在以2m/s的恒定速度运动的足够长的水平传送带上后传送带上留下一条长度为4m的划线.
长度为L=8m的水平传送带以速度v=5m/s匀速向右运动以传送带的左端为坐标原点建立如图所示的xOy
如图所示水平传送带顺时针匀速转动一物块轻放在传送带左端当物块运动到传送带右端时恰与传送带速度相等若
变为原来的一半
变为原来的2倍
不变
变为原来的4倍
水平传送带带速恒定为v1设传送带足够长也足够宽现有一小物块以垂直于传送带边沿的水平速度v2冲上传送带
如图所示x轴与水平传送带重合坐标原点0在传送带的左端传送带OQ长L=8m传送带顺时针速度V=5m/s
如图14所示x轴与水平传送带重合坐标原点0在传送带的左端传送带OQ长L=8m传送带顺时针速度V.=5
12分如图所示的传送皮带其水平部分ab的长度为2m倾斜部分bc的长度为4mbc与水平面的夹角为α=3
如图所示水平传送带以速度v匀速传动一质量为m的小物块
由静止轻放在传送带上,若小物块与传送带间的动摩擦因数为
,已知物块在传送带上先加速后匀速,下列说法中正确的是: A.摩擦力对物块一直做负功
摩擦力对传送带一直做正功
传送带克服摩擦力做功的功率为
此过程中产生的内能为
将一粉笔头轻放在2m/s的恒定速度运动的水平传送带上后传送带上留下一条长为4m的划线若使该传送带做匀
如图所示的传送带其水平部分ab的长度为2m倾斜部分bc的长度为4mbc与水平面的夹角为α=37°.将
三角形传送带以1m/s的速度逆时针匀速转动两边的传送带长都是2m且与水平方向的夹角均为37°现有两个
B.从传送带顶端均以1m/s的初速度沿传送带下滑,物块与传送带间的动摩擦因数均为0.5。下列说法正确的是
A.物块A.先到达传送带底端
物块A.B.同时到达传送带底端
传送带对物块A.B.均做负功
物块A.B.在传送带上的划痕长度相等
如图所示传送带与两轮切点A.B间的距离为l=20m半径为R=0.4m的光滑的半圆轨道与传送带相切于B
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Howtohelpawheelchairuserintoachair Ifyou'relookingaftersomeonewhousesawheelchairknowingthecorrectwaytoassisthiminDtoandoutofhischaircanbequiteimportant.1Soit'snecessarytounderstandhowtolendahandsafelybeforeyouattempttodoso. 1.Preparethechair. It'scrucialtoensurethatthechairisreadyforthepersontositinbeforeyoubegintomovehim.Nevertrytoadjustthechairwhenyou'realreadybearingaperson'sweight.Insteadensurethatthechairisintherightpositionbeforeyoustart.2 2.Liftsafely. Beforeyoucanhelpawheelchairuserintoachairyouneedtobeawareofseveralfactorsaswellasthecorrectwaytoliftthechairuser.Makesureyouknowhowheavyyourfriendorfamilymemberisandthatyou'restrongenoughtolifthimtositsafelyinthechair.3Yourclothingandfootwearisalsoimportant.Ensurethereisnothingyou'rewearingthatcouldcatchandthatyourshoesallowcompletestability. 3.4 Loweryourfriendorfamilymemberintothewheelchairslowlyandsteadilymakingsuretheyarefullyseatedinthechair.Iftheyareabletostandandlowerthemselvesintothechairstandbehinditandholdontothehandlestomakesureitdoesn'tmove.5Beforemovingthewheelchairaskthemtoplacetheirhandsintheirlapormoreimportantlyawayfromthewheelssothattheycanfeelcomfortable. Aboveallcheckthatthepersonyouareassistingiscalmandrelaxedandhappytoreceivehelp. A.Makethemcomfortable. B.Rememberloleavethewheelchairbehind. C.Youshouldheinanareawithnoobstaclesintheway. D.Makesureyoucanhaveafreetalkwiththewheelchairuser. E.Notknowingtherighttechniquescanresultininjurytothewheelchairuser. F.Oncetheyareseatedswingthefootrestsbackintoplacemindingtheirlegs. G.Mostimportantlymakesurethewheelchairbrakesareonandthatthechairistotallystable.
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假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.错误涉及一个单词的增加删除或修改.增加在缺词处加一个漏字符号∧并在其下面写出该加的词.删除把多余的词用斜线\划掉.修改在错的词下划一横线并在该词下面写出修改后的词.注意1.每处错误及其修改均仅限一词2.只允许修改10处多者从第11处起不计分.ItwasattheGreenStorethatIfindabrokenrockingchairandputitinbackofmytruck.Theseatwassplitintotwofromfronttoback.Otherthanthatitwasinexcellentlycondition.IthoughtIshouldrepairitsothatbythefollowingdayitwouldbesogoodasanewone.BySundayafternoonthegluehadsetandaftertwocoatofbrightwhitepaintthechairwasofperfect.IwasexcitingbecauseIwasgoingtosurprisemywife.Wewerenewparenttoabeautifulbabyboy.Ournewbabylovedtoberockedbutwedidn5thaveaproperrockingchair.Thischairwasbeautifulandhiswifewasveryhappywithit.
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Accordingtolegendayoungmanwhilewanderingthedesertcameacrossaspringofdeliciouscrystal﹣clearwater.The1wassosweethefilledhisleathercontainersohecouldbringsomebacktoatribalelderwhohadbeenhis2. Afterafour﹣dayjourneyhe3thewatertotheoldmanwhotookadeepdrinksmiledwarmlyand4hisstudentlavishly浪费地forthesweetwater.Theyoungmanreturnedtohiswitha5heart. Latertheteacherletanotherstudent6thewater.Hespatitoutsayingitwas7.Itapparentlyhadbecomestale不新鲜的becauseoftheold8container.Thestudent9histeacherMasterthewaterwas10.Whydidyou11tolikeitTheteacherrepliedYouonlytastedthewaterItastedthe12.Thewaterwassimplythecontainerforangetofloving﹣kindnessand13couldbesweeter.Ithinkweunderstandthislessonbestwhenwereceive14giftsoflovefromyoungchildren.Whetherit'sanuglyplateorabraceletthenaturalandproper15isappreciationandexpressed16becausewelovetheideawithinthegift. Gratitudedoesn'talwayscome17.Unfortunatelymostchildrenandmanyadults18onlythethinggivenratherthanthefeelingembodied被体现init.Weshouldremindourselvesand19ourchildrenaboutthebeautyandpurityoffeelingsandexpressionsofgratitude.20giftsfromtheheartarereallygiftsoftheheart. 1A.desert B.voice C.spring D.water 2A.master B.teacher C.relative D.friend 3A.took B.presented C.show D.delivered 4A.thanked B.nodded C.laughed D.joked 5A.light B.heavy C.happy D.broken 6A.throw B.pour C.taste D.bring 7A.tasty B.bitter C.hot D.awful 8A.leather B.rubber C.metal D.firm 9A.asked B.added C.challenged D.doubted 10A.fragrant B.delicious C.smelly D.bitter 11A.have B.pretend C.happen D.intend 12A.gift B.meaning C.feeling D.drink 13A.none B.everything C.seldom D.nothing 14A.innocent B.precious C.guilty D.priceless 15A.demand B.response C.comment D.problem 16A.thankfulness B.smile C.laughter D.praise 17A.firstly B.friendly C.immediately D.naturally 18A.ignore B.value C.stress D.forget 19A.tell B.bring C.teach D.send 20A.Asaresult B.Inaword C.Afterall D.Inthemeantime
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FreeEntrytoPalaceofVersailles﹣Save﹩18! ThePalaceofVersaillesisoneofthelargestandmostsplendidcastlesintheworld.Havingaround2143windows1252fireplacesand67staircasesthecastleisoneofthemostvisitedattractionsinFrance. Asafineexampleof18th﹣eenturyFrenchartthishistoricbuilding‘hasbeenonUNESCO'sWorldHeritage遗产Listfor30years. AtfirstitjustuhuntinghousebuiltbyLouisVIII.ButLouisXIVchosethesitetobuildthepalaceweknowtodaythesymbolofroyalabsolutism专权专治andclassicalseatofpowerin1789butgotroleinthe19thcenturyastheMuseumoftheHistoryofFrancewhichwasfoundedwhenLouisPhilippebecamethekingin1830. Thishistoriccastlewithitsbeautifularchitectureandgardensandlonghistoryisa.must﹣visitsightonasightseeingtriptoParis. ◆OpeningTimes HighseasonIApril~31OctobereverydayexceptMondays900~1830.Lastadmission1800. LowseasonNovember~31MarcheverydayexceptMondays900~1730.Lastadmission1700. ◆EntrytothePalace TogettothePalaceofVersaillesbyRERCrailline大区快铁C线makesuretobuyaParis﹣VersaillesRiverGaucheticketzones1~4. WithaParispassyoucanvisitthepalacefreeofcharge﹣that'sasavingofEuros.PleasenotethatVersaillesisoutsidezone3butsingleRERtraintickettoVersaillescostyouonly﹩3.25. WithaParispassyoudon'tneedtoqueueupbutcanuseprivilegedPassholderentryagreatbenefitifyouarevisitingduringthebusyspringorsummerseasons. ◆NoteYourentrydoesnotincludethemusicalfountainshows.Whenthewatershowsaretakingplaceyouwillbeunabletovisitthegardensunlessyoupurchaseaseparateticket. 1WhatcanwelearnaboutthePalaceofVersailles A.Itwasusedasamuseumatfirst. B.ItwasbuiltinmemoryofLouisXIV. C.Itwastheofficialseatofpowerin1830. D.ItisnotsobusyinNovemberasinOctober. 2IfavisitorwantstoenjoythePalaceofVersailleshewill. A.reachzone3ontime B.beallowedtovisititonMondays C.spendsomemoneytakingtheRERtrain D.alsowaitinthequeuelikeothertravelers 3Inordertowatchthewatershowsyouhavetobuy A.aParisPass B.aticketspeciallyforit C.asingleRERtrainticket D.aParisVersaillesRiverGaucheticket
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WhenIwasfiveyearsoldmymothersufferedfromdepression﹣andotherhealthissuesleavingmetocareforher.This1reversedourrolesaschildandcaretaker. WhileIknewmymotherwassickI2thateverythingwouldbeokay.3in1997everythingwenthorribly4andmylifechangedforever. Adoptionisan5wordtoafive﹣year﹣oldbutwhenI6thatmymotherhadsignedmeovertostrangersIfeltitwastheultimatebetrayal.Isufferedfromshock7andconfusionasIattemptedto8mynewfamily.IdidlearntolovemynewparentsthoughIcouldn'tforgivemymotherfor9me.Hearingpeopletellmethatshediditinmybestinterest﹣thatsheactually10me﹣mademebitter.Iinsistedthat11shehadtrullylovedmsshewouldhavemadeitworkforourlittlefamily. HowevertheolderIgotthemoreIbegantounderstandhow12oursituationhadbeen.Wehadbeen13boxesofnoodlesandweevenlivedinourcar.Ihavestartedtounderstandthe14sheputmeupforadoptionandthatshereallydidsaveme. OnlyrecentlyhaveIbegunto15howamothercouldgiveherchildtostrangersandIrealizenowwhatasacrificeitmusthavebeenforhertoletmego.Shewas16buteveninherstatesheunderstoodthatshewaspullingmedownwithher.Shelovedme17anythingsoshewantedmetohaveachanceinlifeonesherealisedshecouldnolonger18me.WhenIlookbacknowIam19toher.EventhoughIresented怨恨herforalongtimeInowknowmylifehasbeenaspecilagiftonlybecauseshewas20enoughtogivemeup. 1A.trend B.direction C.situation D.operation 2Arecognized B.believed Cadmitted D.explained 3A.However B.Therefore C.Otherwise D.Besides 4A.well B.wrong C.mad D.common 5A.exact B.right C.warm D.foreign 6A.regretted B.wondered C.realized D.expected 7A.cold B.hunger C.tiredness D.anger 8A.giveup B.worryabout C.adjustto D.searchfor 9A.rejecting B.raising C.criticizing D.accompanying 10A.blamed B.loved Cfeared D.forgot 11A.although B.if C.since D.unless 12A.familiar B.simple C.desperate D.stable 13A.throwingaway B.chargingfor C.dreamingof D.survivingon 14A.reasons B.risks C.rules D.results 15A.remember B.understand C.ignore D.describe 16A.upset B.sick C.polite D.calm 17A.otherthan B.ratherthan C.morethan D.lessthan 18A.lend B.control C.teach D.offer 19A.grateful B.similar C.equal D.rude 20A.curious B.patient C.selfless D.careful
已知函数fx=|x﹣3|. 1若ft+f2t<9求t的取值范围 2若存在x∈[24]使得f2x+|x+a|≤3成立求a的取值范围.
ThereisarestaurantinmyMainetownthathasdonelittletoupdateitselfoverthepast80years.Thisispartofitscharmasisthewoodenphonebooththatsitsneglectedintheageofthecellphone.Ahthephonebooth.Weneeditnowmorethanever. Formeitsymbolizesthatphonecallswereonceprivateaffairseveniftheinformationbeingsharedwasnotsensitiveinanyway.Itwassimplyassumedthataphonecenversationwasmeantfortwopeopleandtwopeopleonly. Growingupinthe1960swehadonlyphoneinthehouse.AsakidIdidn'tgetormakemanycallsbecauseallmyfriendsfivewithinearshotandIcouldjustyelloutthewindowifIwantedtheirattention.IdohoweverrememberansweringthephoneaskingfortheidentityofthecallerandthenhandingthephonetomymomShe'dtakeitsayHelloMrs…onemomentpleaseandthenassheplacedherhandoverthereceiversheturnedtomeanddirectedThisisforme.Whydon'tyougooutsideandplay Flashforwardtowhatcellphoneshavedonetoourlife.Withinthespaceofafewyearsoverhearingprivateconversationsseemstobenormal.NotlongagoIwassittinginBoston'sSouthStationnearamanwhowasonhiscellphonewaitingformytrain. ThefollowingiswhatthemanhadtosayYesthat'sright.Theredandyellowroses.Thenhecontinuedtorecitehiscardnumberaridexpirationdate有效期.Istaredatthefellow.HeglancedatmeandaskedWhatMyresponsewasimmediateIrecitedhiscardnumberbacktohimalongwiththeexpirationdate. Thereisnolongerasenseofpersonalbordersorlimits.Thecellphonehasbecomeamegaphone扩音器andIhavebeenprivy私下知情todetailsofpeople'slivesthatIwouldrathernotknow.Maybephoneboothscouldserveascellphoneharborstoday. 1WhatfeaturedoestherestaurantinMainetownhave A.Itisverypopular B.Itisold﹣fashioned C.Itwillclosedown D.Ithasbeenneglected 2Asakidtheauthor A.hadafewfriends B.oftencalledhisfriends C.wasnotallowedtoanswerthephone D.learnedthatphoneconversationsareprivate 3Whatistheauthor'sattitudetowardscellphone A.Critical B.Tolerate C.Optimistic D.Approving 4WhatdidtheauthordoinBoston'sSouthStation A.Hetalkedtoanoldfriend. B.Heboughtsomecolorfulroses. C.Heoverheardaman'spersonalinformation. D.Hehelpedastrangerwhowasmakingacall.
Theaye﹣ayeinthesamefamilyaspeoplemonkeysandapesisabout40cmlongwithabushytaleaboutthesamelengthasthebody.Thedarkbrownfurislongandwoollygivingtheanimalarathershaggy蓬松的appearance.TheyarefoundonlyonMadagascaranislandoffthecoastofAfrica.ItlivesinthetropicalforestsintheeastandnorthofMadagascar. Theaye﹣ayeismostlyarboreal栖息在树上的butissometimesseenwalkingontheground.It'sactiveduringthenightlookingaroundinthetreesforfood.Theaye﹣ayeisactuallythelargestprimate灵长类动物activeduringthenight.Largeeyeshelptheaye﹣ayefinditswayaboutatnight.Duringthedaytheaye﹣ayesleepsinanestinatree.Aye﹣ayesspendalmostthewholenighttravellingaboutandfeeding. Aye﹣ayeslivealone.Sometimespairsareseenbutbasicallylittleisknownabouttheirlives.Theydon'tleapandclingtotreeslikeotherprimates.Theymoveaboutonallfourlegs.Theyoccasionallymakebriefcriesbutareusuallysilent.Wormsinsidedeadwoodformthelargestpartoftheaye﹣ayediet.Theaye﹣ayealsofeedsonfruiteggsandbambooshoots. Thefrontfeetoftheaye﹣ayeareunique.Allthetoesarelongandthinbutthethirdisexceptionallylong.Theaye﹣ayetapsonthetreetrunkandlistensformovementasitsearchesforplaceswherewormsmightbelocated.Itbitesatthetreetomakehomesthenitusesitslongthirdfingertoreachinsideandhookoutworms.Thefrontteethoftheaye﹣ayegrowcontinuouslyandareworndownbyitseatingatbarkinitssearchforworms. Aye﹣ayesareclosetobegoneortotallygone.Becauseofdeforestation伐木orforestdestructiontheanimalshavethereforebeenforcedtoeatvillagers'cropsandmanyaye﹣ayeshavebeenkilledwhiledoingso.InadditionsomepeopleonMadagascarwillbelievethatseeinganaye﹣ayeisasignthatsomeoneclosetothemwilldiesotheykilltheanimalsonsight. 1Accordingtothefirstparagraphtheaye﹣aye. A.lookscolorful. B.hasahairlesstail. C.likesthehotplaces. D.soundslikemonkeys. 2Theaye﹣aye'sthirdfingerismainlyto. A.makeholesbigenough B.reachintotheholeforfood C.helpwalkfastontheground D.gettheanimalstofixonthetree 3Whatarereducingthenumberofaye﹣ayes A.People'sactivities. B.Environmentchanges. C.Globalwarming. D.Environmentalprotection. 4Whatisthepurposeofthepassage A.Toprotecttheaye﹣ayes. B.Tostopforestsbeingdestroyed. C.Tomaketheaye﹣ayeslivebetter. D.Tointroducetheaye﹣ayes.
已知函数fx=xlnx﹣axa∈R. 1求函数fx的单调区间 2若fx+a≥0恒成立求a的值.
Indonesiaishometofouroftheworld'sworstpollutedriversandrankssecondwhenitcomestoplasticwaste.Sincesingle﹣usepackagingisalargecontributortotheproblemEvowareanIndonesian﹣basedcompanydecidedtohandlethatissuefirst.Andnowakindofedible可食用的packetshasbeeninvented. Afterinvestigatingvariousmaterialoptionsthecompanysettledonseaweed.Unlikecomcommonlyusedforcontainersseaweeddoesnotrequireresourceslikewaterorlargeamountsofspace.AccordingtoEvowareasmuchas40tonsofseaweedcanbegrowninanareathesizeofabaseballfield.Italsohelpsabsorbharmfulgreenhousegaseslikecarbondioxide.SinceIndonesianfarmersalreadyharvestmoreseaweedthantheycansellitiseasyforthecompanytofindthematerial. ThoughtheywillnotmakepublictheirproductionprocessEvowareannouncestheseaweedpackagingcontainsnochemicalsandissafetoconsume.Inadditiontowrappingfastfooditemsitcanalsobeusedtohousethingslikeinstantnoodleseasoning调味品andinstantcoffee. Thoughtheediblewrappersmaynothaveanytastethesamecannotbesaidaboutthesingle﹣usecupsthatthecompanyhasalsoinvented.Thesingle﹣usecupsthatcanbeusedtoservecolddrinksareavailablewiththetasteoforangeandgreentea. Whilereplacingplasticwiththeseaweedproductsmayseemlikeano﹣brainertomostofusitisahard﹣sellinIndonesia.AccordingtoChristianTheawarenessunderstandingandsenseofurgencytominimizetheuseofsingle﹣useplasticarestillverylow.Alsoafactoristhecostwhichishigherthanusingplastic. HopefullyEvowarewillsucceedinconvincingIndonesiansandpeopleworldwidethatswitchingtotheirproductswillgoalongwayinprotectingourbeautifulplanet. 1WhatisEvoware'spurposeofinventingeatablepackages A.Tomakefulluseofseaweed. B.Tomakegenerousprofits. C.Toattractmorecustomers. D.Toreduceplasticpollution. 2Whatcanwelearnaboutseaweedfromparagraph2 A.Itiseasytoget. B.Itbreaksdowneasily. C.Itishardtoharvest. D.Itcangrowinabaseballfield. 3Howaresingle﹣usecupsdifferentfromseaweedpackaging A.Theyarebeautiful. B.Theyhavedifferenttastes. C.Theyareinvariousshapes. D.Theyareenvironmentallyfriendly. 4Whatstopstheseaweedproductsbeingwidelyused A.Thehighcost. B.Theterribletaste. C.Thelackofseaweed. D.Thecomplexproductionprocess.
TheearthhaschangedoverandoveragainthroughoutthecourseofitshistoryInordertosurviveinchangingenvironmentsspeciesmustoftengothroughaprocessofadaptation.Adaptationreferstogeneticchangethatenablesanorganism生物体suchasananimalorplanttosurviveinitsenvironment.Iftheorganismsofaspeciescannotchangealongwiththeareainwhichtheylivetheyriskdyingout.Recenthistoryhasgivenusanimportantexampleofhoworganismsareabletosurviveoncetheirenvironmentschange. Lightgraypepperedmoths胡椒蛾anddark﹣coloredpepperedmothslivedinthecountrysidebetweenthecitiesofManchesterandLondoninEnglandManyyearsbeforethe19thcenturymoreofthelightgraypepperedmothshadbeenabletosurviveintheirenvironmentmostlybecauseoftheircolor.Birdscouldn'tseethelight﹣coloredmothsonthetreesbecausethecolorofthemothswassimilartothecolorofthetrees. Intheearly19thcenturythoughEnglandbeganthefirstyearsofitsIndustrialRevolution.Manyareasbecameoccupiedbyagrowingnumberoffactories.Manyofthesefactoriesneededcoaltoprovideenergyfortheirmachines.Whencoalbumsitgivesoffalotofdark﹣coloredsmokes.Thetreesbegantoblackenbecauseofallthesmokeintheairfromthefactories.Thismadethelightgraypepperedmothsmuchmorevulnerable.Birdscouldseethemonthetreesmoredearlyandeasilyhuntthemdown. SometimeinthenexthundredyearsscientistsbegantonoticeahugechangeinthemothpopulationlivinginandbetweenthecitiesofManchesterandLondon.Mostofthepepperedmothswereofthedark﹣coloredkind!Whatcausedthischangewasthefactthatbirdshadeatenalotofthelightgraypepperedmothsbecausethemothscouldbeseenclearlyonthedarkenedtrees.Thedark﹣coloredpepperedmothsintheareasurvivedmuchmoreeasilyandmatedwithotherdark﹣coloredpepperedmothsuntilmostofthepopulationofpepperedmothsbecamedark﹣colored. 32.Ifaspeciescan'tadapttothechangingenvironmenttheyarelikelyto. A.bedrivenoutoftheirhabitat. B.becomeextinct C.movetoanotherenvironment D.gothroughgeneticchanges 33.Whatconclusioncanbedrawnfromthechangeintwokindsofmoths A.Therewerepreviouslynodark﹣coloredpepperedmoths. B.Thelight﹣coloredpepperedmothsmovedtoanewenvironment. C.Thecolorchangehadnothingtodowiththechangeintheirenvironment. D.Darkcoloringwasbetterforthepepperedmothssurvivalinthe19thcentury. 34.Whatdoestheunderlinedwordvulnerableprobablymean A.Quicktochange B.Opentoattack C.Easilydefended D.Inastrongposition 35.Whatdoestheauthormainlydescribeinthepassage A.HowtheIndustrialRevolutionimprovedthelivesofworkers. B.Howtheearthchangedthroughoutthecourseofitshistory. C.Howhumaninfluenceorganismsthroughartificialselection. D.Hownaturalselectionchangedthepopulationofpepperedmoths.
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